Methods and biocompatible compositions to achieve sustained drug release in the eye

ABSTRACT

A nanostructured biocompatible wafer for drug delivery to a tissue. The wafer contains a tissue-reactive mucoadhesive polymer and a mesh formed of a plurality of polymer fibers. Also provided is a method for treating an ocular surface disease, disorder, or infection using the nanostructured biocompatible wafer. Additionally, an injectable sustained-release formulation for treating an ocular disorder is disclosed. The formulation includes a drug contained within a plurality of microparticles formed of a biodegradable polymer and are coated with a tissue-reactive compound. Further provided is a method for treating an ocular disorder by injecting the microparticulate sustained release formulation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/509,083, filed on Mar. 6, 2017, which is the National Stageof International Application No. PCT/US2015/048795, filed on Sep. 8,2015, which claims priority to U.S. Provisional Application No.62/046,918, filed on Sep. 6, 2014. The content of these threeapplications is hereby incorporated by reference in its entirety.

BACKGROUND Field

This application relates to methods and compositions for administeringpharmaceutical compositions to the ocular surface, the anterior chamber,and the posterior chamber of the eye for treating ocular diseases anddisorders.

Background Information Limitations of Current Therapies for the Eye

Currently, most ophthalmic drugs are administered in the form ofeye-drops. With a single eye-drop, only about 5% of the drugadministered is absorbed by ocular tissue; the rest is lost throughnaso-lacrimal drainage. Additionally, fast drainage of eye-dropformulations from the ocular space makes frequent administrationregimens necessary. This leads to patient's incompliance due toinconvenience, leading to a lower therapeutic value of the treatment.

Most ophthalmic drugs are hydrophobic small molecules. For this reason,liquid eye-drops are typically suspensions due to the limited solubilityof ophthalmic drugs in water. For drug suspensions to be bioavailable,the drug must be solubilized first in the eye prior to absorption. Thefast clearance rate of fluid from the eye results in low drug absorptionrates and inefficient delivery.

On the other hand, fully solubilized drug eye-drop solutions lead tospikes in drug concentration levels followed by fast clearance. Thisleads to possibly irritating high levels of drug followed by less thantherapeutic levels of the drug.

Most commercial formulations of prostaglandins for glaucoma treatmentcontain a commonly used preservative, benzalkonium chloride, which hasbeen correlated with ocular toxicity in both in-vivo and in-vitrostudies, including corneal neurotoxicity. Chronic use of a preservativehas been correlated with apoptosis of conjunctival cells and inductionof inflammation. Thus, preservative-free strategies for glaucomatreatments should be part of the design space for future therapeuticregimens.

Historically, sustained-release delivery systems were designed toprovide continuous release of a therapeutic agent to avoid the peak andtrough therapeutic agent levels that occur in the aqueous humor withtopical dosing. Sustained release delivery systems for front-of-the-eyeocular delivery include, e.g., viscous solutions to enhance residencetime, punctal plugs, and drug-coated contact lenses. All of thesesystems have advantages over eye-drops and distinct disadvantages. Forexample, in addition to manufacturing challenges, drug-eluting contactlenses impact the vision field with inherent alterations in the visualacuity of the lens as the drug depletes, and punctal plugs requireinstallation by a clinician.

Turning to therapy for diseases in the posterior chamber of the eye,drugs are typically injected in the vitreous, sub-tenon's, orsuprachoroidal tissue space. Multiple injections into the back of theeye can increase the risk of infections and retinal detachment. Thus,sustained release systems have become the answer to the treatment ofchronic ocular disorders, obviating the need for frequent injections.

Biodegradable implants and poly(lactic-co-glycolic acid) (PLGA)microspheres have been most commonly used for sustained release drugdelivery. In the case of microspheres, the manufacturing processgenerates microspheres which have a size distribution. Depending uponthe process, the size distribution of the delivery system can varywidely, resulting in wide variations in drug release. Wide sizedistributions can result in a release rate that is not precise orpredictable, since the rate of diffusion of a drug through a matrix isdependent upon its path length. Other factors affecting release rate arepolymer composition, rate of hydration of the microsphere matrix, anderosion of the matrix due to biodegradation. Thus, matrices with smallersizes have shorter diffusion path-lengths and faster degradation rates,leading to faster drug release.

It is difficult to achieve a constant rate of drug release per unit timefor PLGA microspheres prepared by standard techniques. Typically, whatis observed is a “burst” of drug followed by a “trickling” of drug fromthe matrices, until the matrix disintegrates completely, leading tosudden, unpredictable, and complete release of encapsulated drug, i.e.,dose dumping. Dose dumping can lead to undesirable and unanticipatedside effects due to drug toxicity. Tighter control of microsphere sizehas been accomplished by sieving methods, although this often leads tosignificant losses of encapsulated drug due to the difficulty of sievingto narrow particle size ranges.

Additionally, microspheres tend to aggregate into a mass when injectedinto a tissue, also leading to unpredictable drug release rates. This isa major issue, since the aggregated microspheres behave like a muchlarger delivery system, having drug release rates dependent on thedimensions and characteristics of the aggregations. Since the shape andinternal characteristic of the aggregates is unpredictable and can varywith each injection, the rate of release of the drug will vary with eachadministration. This leads to variability and unpredictability of drugpharmacokinetics.

As mentioned above, if drug levels are too low, the drug is ineffectiveand if the drug levels are too high, toxicity can result. Thus, inaddition to precise and predictable drug release, a critical need existsto keep the dosage form of microspheres in a dispersed state afterin-vivo administration in order to ensure consistency in drugbioavailability.

Related Art

U.S. Pat. No. 8,409,606 describes a medical prosthesis for blocking orreducing tear flow through a tear duct of a human eye while delivering adrug to the eye. The prosthesis contains a dehydrated, cross-linkedsynthetic hydrophilic polymer containing a therapeutic agent. Theprosthesis is sized to be readily inserted into the patient's tear ductand quickly swells upon insertion to at least 1 mm in cross-sectionalwidth to conformably fit the canaliculus into which it is inserted. Theprosthesis requires a specialized instrument to allow a doctor to insertit into the eye of the patient.

United States Patent Application Publication 2013/0090612 describesdevices which are designed to rest on the surface of the eye out of thefield of vision but surrounding the cornea along at least a portion ofconjunctival sac of the upper and lower lids of the eye. The deviceshave reservoirs containing eye medications. Some of the devicesdescribed in the application are completely non-bioerodible and otherspartially bioerodible.

International Patent Application Publication WO/2011/091205 describesintracameral implants including at least one therapeutic agent fortreatment of an ocular condition. The implants are not anchored to theocular tissue, but rather are held in place by currents and gravitypresent in the anterior chamber of an eye. The polymeric, biodegradableimplants described provide sustained release of at least one therapeuticagent to both the trabecular meshwork and associated ocular tissue andthe fluids within the anterior chamber of an eye. The intracameralimplants must be injected by a clinician and cannot be removed ifunanticipated adverse effects occur without additional surgicalintervention.

United States Patent Application Publication 2012/0276186 describes asustained release, biodegradable polyethylene glycol (PEG) intraocularlatanoprost implant for reducing elevated intraocular pressure. Theimplant can be configured as a film about 100 μm to about 500 μm thickand about 2 to about 6 mm in diameter when unrolled, or an extrudedfilament with a diameter between about 500 μm to 1.5 mm and a lengthbetween about 5 μm to about 10 mm. Either implant is inserted into theeye of an individual via a needle to provide for extended release oflatanoprost for at least 30 days. The implant requires a doctor to putit in place and it cannot be easily removed in the event of an allergicreaction.

United States Patent Application Publication 2004/0241207 describes acontact lens with embedded drug nanoparticles having a particle sizeless than about 200 nm. The embedded drug is capable of diffusion intoand migration through the contact lens and into the post-lens tear filmwhen the contact lens is placed on the eye. The technology hassignificant challenges both in manufacturing and maintaining therefractive power of the lenses due to light deflection occurring as aresult of embedded drug particles.

SUMMARY

To address the issues set forth above, a nanostructured biocompatiblewafer for placement in the conjunctival cul-de-sac is provided. Thewafer contains a tissue-reactive mucoadhesive polymer and a mesh formedof a plurality of polymer fibers. The tissue-reactive mucoadhesivepolymer is coated on the wafer or intercalated with the fibers. Thewafer has a thickness of 0.05 mm to 0.5 mm, a hydrated flexural modulusless than 25 MPa, and an oxygen permeability of 15 Dk to 30 Dk. The meshhas a pore size of 50 nm to 1000 nm, and the polymer fibers have adiameter of 100 nm to 1500 nm.

Also provided is a method for treating glaucoma, an ocular surfacedisorder, or an ocular surface infection by placing the nanostructuredbiocompatible wafer described above also containing a drug into theconjunctival cul-de-sac of a subject and maintaining the nanostructuredbiocompatible wafer in the conjunctival cul-de-sac for a period of 2weeks to 6 months.

Alternatively, an injectable sustained-release formulation for treatingan ocular disorder is disclosed. The formulation includes a drugcontained within a plurality of microparticles. The microparticles areformed of a biodegradable polymer, and are coated with a tissue-reactivecompound. The coated microparticles (i) have a size of 1 μm to 40 μm,(ii) contain 20% to 30% by weight of the biodegradable polymer, and(iii) contain 5% to 20% by weight of the tissue-reactive compound.

Also disclosed is a method for treating an ocular disorder by injectingthe sustained release formulation described above into the eye of asubject suffering from an ocular disorder.

The details of one or more embodiments of the invention are set forth inthe drawings and description below. Other features, objects, andadvantages of the invention will be apparent from the description, thedrawings, and from the claims. The contents of all documents citedherein are hereby incorporated by reference in their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention description below refers to the accompanying drawings, ofwhich:

FIG. 1A is an illustration of a method for placing of a drug-releasingmesh in the eye;

FIG. 1B is a schematic of a method to fabricate the mesh shown in FIG.1A;

FIG. 1C is a scanning electron micrograph (SEM) of atravoprost-containing nanostructured biocompatible wafer produced byelectrospinning;

FIG. 1D are SEMs of travoprost-containing nanostructured biocompatiblewafers produced using three different exemplary process conditions;

FIG. 1E is a magnified SEM of a travoprost-containing nanostructuredbiocompatible wafer showing interconnected conduits of the mesh wafer;

FIG. 2A is a plot of an in-vitro release profile of travoprost from ananostructured biocompatible wafer in phosphate buffer at 37° C.;

FIG. 2B is a plot of release kinetics of travoprost from ananostructured biocompatible wafer;

FIG. 2C is a plot of release kinetics of travoprost from nanostructuredbiocompatible wafers of differing composition;

FIG. 2D is a plot of travoprost amount remaining in a nanostructuredbiocompatible wafer versus time in release buffer;

FIG. 3A is a bar graph showing the ex-vivo corneal permeability oftravoprost released from a nanostructured biocompatible wafer over time;

FIG. 3B is a graph showing the surface pH of the nanostructuredbiocompatible wafer over time during a drug release study;

FIG. 3C is a bar graph showing the amount of travoprost and travoprostacid in the cornea following an ex-vivo corneal permeability assay;

FIG. 4A is a plot of an in-vitro release profile of loteprednoletabonate from a nanostructured biocompatible wafer;

FIG. 4B is a plot of an in-vitro release profile of loteprednoletabonate from microparticles of an injectable sustained releaseformulation;

FIG. 4C is a bar graph showing the amount of loteprednol etabonatereleased from microparticles of an injectable sustained releaseformulation as a function of microparticle size;

FIG. 4D is a plot of an in-vitro release profile of brinzolamide from ananostructured biocompatible wafer;

FIG. 5A is a cross-sectional view of a biaxial fiber for incorporationinto a nanostructured biocompatible wafer and for manufacturingmicroparticles for an injectable sustained release formulation;

FIG. 5B is a cross-sectional view of a tri-annular fiber forincorporation into a nanostructured biocompatible wafer and formanufacturing microparticles for an injectable sustained releaseformulation; and

FIG. 5C is a cross-sectional view of an alternative tri-annular fiberfor incorporation into a nano structured biocompatible wafer and formanufacturing microparticles for an injectable sustained releaseformulation.

DETAILED DESCRIPTION Definition of Terms

“Biodegradable polymer” means a polymer or polymers which degrade invivo, and wherein erosion of the polymer or polymers over time occurconcurrent with, or subsequent to release of the therapeutic agent. Theterms “biodegradable” and “bioerodible” are used interchangeably herein.A biodegradable polymer may be a homopolymer, a copolymer, or a polymercontaining more than two different polymeric units. The polymer can be agel or hydrogel type polymer.

“Ocular condition” means a disease, ailment, or condition which affectsor involves the ocular region. Broadly speaking, the eye includes theeyeball and the tissues and fluids which constitute the eyeball, theperiocular muscles, and the portion of the optic nerve which is withinor adjacent to the eyeball.

An anterior ocular condition is a disease, ailment, or condition whichaffects or which involves an anterior, i.e., front of the eye, ocularregion or site, such as a periocular muscle, an eye lid, or an eye balltissue or fluid which is located anterior to the posterior wall of thelens capsule or ciliary muscles. Thus, an anterior ocular conditionprimarily affects or involves the conjunctiva, the cornea, the anteriorchamber, the iris, the posterior chamber (behind the retina but in frontof the posterior wall of the lens capsule), the lens, or the lenscapsule and blood vessels and nerve which vascularize or innervate ananterior ocular region or site. Thus, an anterior ocular condition caninclude diseases such as aphakia, pseudophakia, astigmatism,blepharospasm, cataract, conjunctival diseases, conjunctivitis, cornealdiseases, corneal ulcer, dry eye syndromes, eyelid diseases, lacrimalapparatus diseases, lacrimal duct obstruction, myopia, presbyopia, pupildisorders, refractive disorders, and strabismus.

A posterior ocular condition is a disease, ailment, or condition whichprimarily affects or involves a posterior ocular region or site such aschoroid or sclera (in a position posterior to a plane through theposterior wall of the lens capsule), vitreous, vitreous chamber, retina,optic nerve, optic disc, and blood vessels and nerves which vascularizeor innervate a posterior ocular region or site. Thus, a posterior ocularcondition includes diseases such as acute macular neuroretinopathy,Behcet's disease, choroidal neovascularization, diabetic uveitis,histoplasmosis, infections such as fungal or viral infections, maculardegeneration (e.g., acute macular degeneration, non-exudative agerelated macular degeneration and exudative age related maculardegeneration), edema (e.g., macular edema, cystoid macular edema anddiabetic macular edema), multifocal choroiditis, ocular trauma whichaffects a posterior ocular site or location, ocular tumors, retinaldisorders such as central retinal vein occlusion, diabetic retinopathy,proliferative diabetic retinopathy, proliferative vitreoretinopathy(PVR), retinal arterial occlusive disease, retinal detachment, uveiticretinal disease, sympathetic ophthalmia, Vogt Koyanagi-Harada (VKH)syndrome, uveal diffusion, a posterior ocular condition caused by orinfluenced by an ocular laser treatment, posterior ocular conditionscaused by or influenced by a photodynamic therapy, photocoagulation,radiation retinopathy, epiretinal membrane disorders, branch retinalvein occlusion, anterior ischemic optic neuropathy, non-retinopathydiabetic retinal dysfunction, and retinitis pigmentosa.

“Ocular region” or “ocular site” means any area of the eyeball,including the anterior and posterior segment of the eye.

“Conjunctival cul-de-sac” is the conjunctival region in the lower eyesocket that is exposed when the bottom eyelid is pulled downward.

“Tissue engineered” refers to polymers that integrate themselves intothe tissues with which they come in contact thereby embedding thetherapeutic agent therein into the tissue for sustained releaseactivity.

“Sustained release” or “controlled release” refers to the release of atleast one therapeutic bioactive agent from an implant at a predeterminedrate. Sustained release implies that the therapeutic bioactive agent isnot released from the implant sporadically in an unpredictable fashionand does not “burst” from the implant upon contact with a biologicalenvironment unless specifically intended to do so. However, the term“sustained release” as used herein does not preclude a “burstphenomenon” associated with deployment.

“Therapeutically effective amount” means the level or amount of agentneeded to treat an ocular condition, or reduce or prevent ocular injuryor damage without causing significant negative or adverse side effectsto the eye or a region of the eye.

“Glaucoma” is a disease of the anterior chamber. Intraocular pressure(IOP) variation appears to be an independent risk factor forglaucomatous damage.

“Electrospinning” refers to a process that generates polymer fibers togenerate a weave, or a mesh-like material. Electrospinning uses anelectrical charge to draw very fine (typically on the micro or nanoscale) fibers from a liquid.

“Microencapsulation” refers to a process that generates polymericencapsulates containing a drug.

Embodiments

Disclosed is a drug-containing nanostructured biodegradable,biocompatible, flexible mesh wafer that can be placed by a caregiver ora patient into the patient's conjunctival cul-de-sac (see FIG. 1A) todeliver a medication short-term or long-term. The drug release rate canbe modulated to achieve therapeutic drug concentrations at the targettissue to persist for at least 1 week, 1 month, 2 months, 3 months or 6months. The nanomesh wafer resulted from a bioengineering approach toadminister medications to the eye, unlike the related art discussedabove. The thickness of the nanomesh wafer, its flexural modulus, andits oxygen permeability are important aspects for long termbiocompatibility, in addition to its sustained release profile andtimely biodegradation. Additionally, the interconnected nano-sized poresand mesh structure of this drug delivery system are conduits for fluidflow in, around, and through the wafer, much like an extra-cellularmatrix. This allows the wafer to be highly hydrated, reducing foreignbody reaction and conjunctival surface damage.

The nanomesh wafer can be formed of monolithic, co-axial, or tri-axialfibers, with one drug or multiple drugs, with varied compositions thatcontrol biodegradation and drug release. See FIGS. 5A, 5B, and 5C. Oneimportant aspect of the nanomesh wafer is the presence of components inthe mesh that crosslink with other components in the mesh as well aswith the tissue to hold the device in-place long term. Another importantaspect of the mesh is the inclusion of membrane-compatible componentsthat make the nanomesh wafer highly biocompatible with ocular tissue.

The nanomesh wafer solves the drawbacks of eye-drop delivery ofophthalmic medications described above. It is a platformsustained-release drug delivery system and can be used to deliver drugsto treat disorders of the anterior chamber and ocular surface. Theseinclude but are not limited to, corneal keratitis, allergicconjunctivitis, post-surgical inflammation, (cataract, glaucoma, cornealtransplant), blepharitis, corneal tear/injury, dry eye, fungalinfections, and corneal methicillin resistant Staphylococcus aureus(MRSA) infection, and glaucoma.

Dimensionally, the nanomesh wafer is appropriately sized to fit into theconjunctival cul-de-sac. It is flexible and contains ingredients thatimpart flexibility to render it biocompatible with the tissue surface.As such, the modulus of the insert is less or equal to that of thetissue surface. The nanomesh wafer can be placed on the surface of theeye on the conjunctiva. It is neither an injectable nor an implant. Itis an insert that rapidly hydrates and adheres to the ocular surface.The nanomesh wafer is not placed on the cornea and does not disrupt thevisual field.

The size of the nanomesh wafer can be appropriately sized to fit theconjunctival space of the human eye. Preferably, the size of thenanomesh wafer is 0.1±0.05 mm thick, 5±0.5 mm wide, and 10±0.5 mm long.

Structurally, the wafer is a drug-containing nanostructured mesh thathas interconnecting open-celled pores. See FIGS. 1C, 1D, and 1E. Themesh size of the interconnecting pores can be 100-200 nm, 200-300 nm, or300-600 nm. Alternatively, the mesh size is a combination between100-600 nm. The thickness of the nanomesh wafer is between 0.05-0.5 mm,preferably between 0.05-0.1 mm.

The nanostructured wafer can be biodegradable, and can be formed of, butnot limited to the polymers polylactide-co-glycolide (PLGA), polylacticacid (PLA), polycaprolactone (PCL), poly(trimethylene carbonate),poly(amino acids), hyaluronic acid, polyethylene glycol (PEG),polyethylene oxide-polypropylene oxide-polyethylene oxide tri-blockcopolymer, PEG-stearate,PEG-distearoyl-sn-glycero-3-phosphoethanolamine, lecithin, xanthan,polyvinylalcohol, polyvinylpyrrolidone, albumin, collagen, or anycombination of these biodegradable polymers.

Preferably, the biodegradable polymers are available commercially andapproved for human use.

In another embodiment, the nanostructured wafer is not biodegradable.This wafer can be formed of polymers having high oxygen permeability.For example, polysiloxanes and polymethylmethacrylate (PMMA) polymerscan be used to form the nanostructured wafer. The non-biodegradablewafer can be removed intact from the conjunctival cul-de-sac at any timeduring or following treatment.

In another embodiment, the nanostuctured wafer is formed of a mix ofbiodegradable and non-biodegradable polymers. The polymers can be any ofthose listed in the preceding paragraphs.

The nanostructured wafer can be produced to have a hydrated flexuralmodulus similar to that of conjunctival tissue. Preferably the hydratedflexural modulus of the wafer is between 10-25 mPa.

In another aspect, the nanostructured wafer can have high oxygenpermeability. The oxygen permeability can be 15 Dk to 30 Dk (e.g., 15,20, 25, and 30). In a particular embodiment, the oxygen permeability ofthe wafer is 25 Dk.

The drug incorporated in the nanomesh will be contained in thebiodegradable portions. To incorporate, the drug and the biodegradablepolymer are dissolved in a suitable organic solvent such as ethylacetate, ethanol or acetone and electrospun using optimized conditionson to a collector plate. The biodegradable polymer or polymer blendreleases drug as the matrix degrades and as the drug finds diffusivepaths through the matrix. The rate of degradation is modulated by thecomposition of the nanomesh wafer. See FIGS. 2A, 2B, and 2C.

Another aspect of the nanomesh wafer is that it is designed to bind tothe ocular conjunctiva either by ionic bonding or by light complexationof proteins on the tissue surface with moieties on the nanomesh. Assuch, these moieties may be thiolated, or aminated.

The nanomesh wafer can contain mucoadhesive tissue-reactive componentsthat have reactive groups that react with the ocular tissue surface.Mucoadhesive properties can be incorporated by inclusion of a chargedpolymer on the surface or intercalated with the drug-loaded fibers. Thecharged polymer can be, but is not limited to, xanthan gum, guar gum,chitosan, hyaluronic acid, alginate, xyloglucans, polycarbophil,polyacrylic acid, tamarind seed polysaccharide, or a polyamino acid,such as polylysine.

The nanomesh wafer can be applied as a dry drug-containing system, whichwill rapidly hydrate and adhere to the conjunctival tissue. In anotherembodiment, the wafer is applied moist in a fully hydrated state. Thehydrating liquid can be, but is not limited to an albumin solution, asolution containing hyaluronic acid, or saline.

In another embodiment, the nanomesh can be drug-free and utilized as awound healing aid.

Additionally, the nanomesh wafer can contain more than one distinctlayer, one over the other, with each layer imparting specific functionalproperties to the wafer. The layers may be intercalated within eachother like a “weave,” imparting properties of mechanical strength,flexibility, or biocompatibility. For example, one layer can contain adrug in a polymer matrix and the other layer can contain thetissue-reactive ingredient. One layer may contain one drug and anothermay contain another drug. For example, an antibiotic and ananti-inflammatory steroid may be incorporated in separate layers withdifferent release rates engineered for each drug.

The nanostructured mesh wafer described above can be produced byco-axial fiber spinning. In this embodiment, the fiber produced by thisprocess, as shown in FIG. 5A, will be a co-axial filament, with the core(2) being the drug-containing biodegradable polymer and the outer layer(1) being a mucoadhesive polymer. In another embodiment illustrated inFIG. 5B, the fiber can be produced as a tri-axial filament having aninner drug-containing polymer (5), a second drug-containing polymer (4)surrounding the inner drug-containing polymer (5), and an outer polymerlayer (3) formed of a mucoadhesive polymer. Alternatively, a tri-axialfilament can be prepared that contains three drug-containing cores (7,8, 9) embedded in a layer (10) of a mucoadhesive polymer that can alsocontain a drug.

In another embodiment of the nanomesh wafer, biodegradabledrug-containing microspheres can be sprayed onto the mesh to create amicrosphere/mesh composite, to achieve the requisite drug releaseproperties.

The nanomesh wafer can be prepared through various methods of fiberspinning. For example, the fibers can be formed by electrospinning,electrospraying, melt extrusion, solvent extrusion, micro-weaving, meltspinning, wet spinning, fiber drawing, or a combination of thesetechniques. The nanomesh wafer can be formed by a combination ofsolution casting and fiber spinning. The layers may be formed by using afine micronized ultrasonic spray of a solution containing a mucoadhesivepolymer described above over a previously formed nanomesh mat. Theultrasonic spray will form a monolayer of the mucoadhesive polymer onthe nanomesh wafer. The mesh can also be produced by 3D printingtechniques. The nanomesh wafer can be produced in rolls or sheets, driedunder vacuum, and cut to size.

In the case of glaucoma therapy, the nanomesh wafer can be manufacturedfrom polymeric materials that quickly meld with the conjunctival tissueof the conjunctival cul-de-sac. Upon insertion, the drug-containingwafer is designed to hydrate and mold itself to the conjunctiva andbegin sustained release of an anti-glaucoma therapeutic through thecornea and into the anterior chamber of the eye.

The nanomesh wafer described above can be preservative-free to avoidpreservative-induced toxicity after long-term use. In an alternativeembodiment, the nanomesh wafer contains a preservative.

The wafer can be sterilized and packed in a foil sterile pack that isimpermeable to moisture and gases. For example, the nanomesh wafer canbe sterilized by ethylene oxide, gamma irradiation, or UV light. Inanother example, each component of the wafer prior to forming fibers issterile filtered and the nanomesh wafer is formed aseptically.

The drug incorporated into the nanomesh wafer can be a small molecule ora macromolecule such as a protein, a peptide, and a nucleic acid.

In a particular embodiment, the drug incorporated into the nanomeshwafer can be a glaucoma drug. For example, the drug can be, but is notlimited to, a prostaglandin, a prostaglandin analogue, and a prostamide.

In one aspect, the prostaglandin incorporated into the nanomesh can belatanoprost, tafluprost, unoprostone, or bimatoprost.

In addition to the drugs listed above, any drug that lowers IOP can beincorporated into the nanomesh wafer. For example, brinzolamide andtimolol can be incorporated into the nanomesh wafer.

The nanomesh wafer can contain a total amount of prostaglandin, perwafer, from 0.5-1000 μg, e.g., 0.5-50 μg, 1-200 μg, 50-100 μg, 100-200μg, and 200-1000 μg. Preferably, the amount of prostaglandin in thewafer will be in the range of 100-350 μg.

In a specific embodiment, the nanomesh wafer can be used in a method fortreating glaucoma by the sustained release of travoprost for 30 days.See FIGS. 2A and 2B. In another embodiment, the nanomesh wafer can beused to treat glaucoma by sustained release of brinzolamide for 30 days.See FIG. 4D. In another embodiment, the glaucoma medication may bereleased for a longer period of time, e.g., 60 days. In anotherembodiment, the glaucoma medication may be released for 90 days, 120days, or 180 days. The nanomesh wafer can be manufactured to modulatedtravoprost release such that a “burst” is followed by sustained release.In one embodiment, a particular release rate of travoprost can beachieved by changing the composition of the wafer. See FIG. 2A andEXAMPLE 1 below.

In another embodiment, the wafer may contain two anti-glaucoma drugs incombination to achieve the required therapeutic effect. For example, thetwo glaucoma drugs can be brinzolamide and travoprost. In anotherembodiment, the two drugs are brinzolamide and brimonidine tartrate.

In another example, the nanomesh wafer can contain both ananti-inflammatory and an anti-microbial. Preferably, the nanomesh wafercontains loteprednol etabonate and tobramycin.

The duration of drug release can be optimized to release the drug in therange between, e.g., 1-7 days, 1-15 days, 1-30 days, 1-45 days, 1-60days, 1-75 days, 1-90 days and 1-180 days.

The absolute amount of drug per nanomesh wafer can be between 0.001-0.1μg, 0.01-0.1 μg, 0.1-0.5 μg, 0.5-1 μg, 1-10 μg, 10-100 μg, 100-500 μg,500-1000 μg, 1000-2000 μg, 2000-5000 μg, and 5000-10000 μg.

As mentioned above, drug-containing nanomesh wafers can be used to treatinfections of the eye and disorders related to microbial infections,such as conjunctivitis, keratitis, blepharitis and rosacea. Ophthalmicantibiotics are available from a variety of drug classes includingaminoglycosides, macrolides, polypeptides, quinolones, and sulfonamides.In addition, many are available as combination products with otherantibiotics or corticosteroids. Any of these existing approvedophthalmic antibiotics can be loaded into the nanomesh wafer describedherein.

The antimicrobial incorporated in the nanomesh wafer described above canbe, but is not limited to moxifloxacin, azythromycin, mupirocin,erythromycin, ciprofloxacin, netilmycin, besifloxacin, gatifloxacin,gentamycin sulfate, levofloxacin, ofloxacin, sulfacetamide sodium,tobramycin, bacitracin zinc, Polymyxin B sulfate, neomycin, and neomycinsulfate.

The nanomesh wafer offers advantages over current ocular antimicrobialformulations. More specifically, the nanomesh wafer described above canefficiently deliver a small dose of antibiotic to ocular tissues atconcentrations greater than the minimum bacteriocidal concentration toeffectively eliminate the bacteria. Lower concentrations of drug thatare less than the minimum bacteriocidal concentration, such as the dosesachieved by antibiotic eye drops can lead to the bacteria evolving tobecome drug resistant. This mode of delivery can lower the incidence ofMRSA. In one embodiment, the nanomesh wafer contains mupirocin, a drugutilized to treat MRSA in nasal linings.

In another aspect, the nanomesh wafer can contain an anti-viral drug.The anti-viral incorporated in the nanomesh can, in a particularembodiment, be used to treat herpes simplex virus (HSV). The anti-viralused to treat HSV can be, e.g., acyclovir, valacyclovir, andfamciclovir. The anti-viral incorporated in the nanomesh can be used totreat viral conjunctivitis.

The drug incorporated in the nanomesh wafer can be used to treat ocularrosacea. Patients displaying clinical symptoms of ocular rosaceatypically also have dermal rosacea. Ocular rosacea is characterized byredness, crusting of the eyelid, itching and irritation. Currently,there is no treatment. The drug can be a therapeutic that is currentlyin testing or under FDA approval for dermal rosacea. The drug can be onethat is used to lower inflammation in tissues. The drug can beoxymetazoline hydrochloride, cetirizine hydrochloride, fluticasonepropionate, fluticasone furoate. The drug used to treat ocular rosaceacan be an anti-allergy medication.

The drug incorporated in the nanomesh can be used to prevent or treatocular pain. In this example, the drug incorporated in the nanomesh isan analgesic. The drug is selected from bromfenac sesquihydrate,amfenac, nepafenac, aspirin, ibuprofen, ketorolac tromethamine, or anyother drug that has analgesic and anti-inflammatory activity.

Alternatively, the drug incorporated in the nanomesh can be ananesthetic. The drug can be but is not limited to lidocaine andnovocaine.

The nanomesh can be formulated to contain wound healing components.Specifically, the nanomesh may contain purified 1→3 beta glucan, or 1→6beta glucan. In one example, the nanomesh contains purified tamarindseed polysaccharide. In another example, the nanomesh contains acombination of albumin, lecithin, collagen, hyaluronic acid, betaglucan, and tamarind seed polysaccharide.

In a further example, the nanomesh can contain components that willlubricate the ocular surface. Examples of such components are xanthangum, hyaluronic acid, and tamarind seed polysaccharide, or combinationsthereof. In another example, the nanomesh can contain lipids and amucoadhesive.

In one example, the nanomesh can be used to treat dry eye in a sustainedfashion. Furthermore, the nanomesh can contain a dry-eye medication,such as cyclosporine.

In another embodiment, the nanomesh wafer can contain ananti-inflammatory. The anti-inflammatory incorporated in the nanomeshincludes but is not limited to loteprednol etabonate, fluticasonepropionate, dexamethasone, dexamethasone phosphate, prednisolone,prednisolone phosphate, budesonide, triamcinolone acetonide,indomethacin, diclofenac, nepafenac, bromfenac, pranoprofen, and anyother drug that may have anti-inflammatory activity.

In a particular embodiment, the nanomesh wafer can be used to treatallergic conjunctivitis by sustained release of loteprednol etabonatefor 20-60 days, as shown in FIG. 4A.

In another aspect, the nanomesh contains an anti-fungal medication.Itraconazole, Posaconazole, Voraconazole and other anti-fungal compoundsknown to have anti-fungal activity can be incorporated into the nanomeshwafer.

The nanomesh wafer is designed to be non-irritating to the surface ofthe eye. A novel correlation of wafer thickness to ocular irritation isdisclosed. See EXAMPLE 1 below. For the wafer to be non-irritating, itshould be <0.5 mm thick. The non-irritating nature of the wafer is alsoa function of its composition and flexibility.

In addition to the nanomesh wafer, an injectable sustained-releaseformulation containing micro- or nano-sized drug encapsulates fortreating ocular disorders is disclosed. The injectable sustained-releaseformulation can be used to deliver both front-of-the-eye medications andback-of-the-eye medications. For front-of-the-eye disorders, thesustained-release formulation is injected into the tissue in theconjunctival cul-de-sac via a syringe to obviate the need for multipleeye-drop administrations. For posterior segment disorders,medication-containing encapsulates are injected into the vitreous,sub-retinal space, supra-choroidal space, sub-Tenon's space or any otherspace known to the clinician to access the posterior ocular space. Theformulation is not limited to treating disorders of the eye. Theformulation can be used to treat a multitude of conditions and disordersin different tissues, e.g., the eye, skin, wounds, urogenital tract,brain, pulmonary, and nose.

The injectable sustained-release formulation contains encapsulates thatare precisely engineered to a defined size, shape, and specific internalmicrostructure. Size, shape, and microstructure are modulated to releasea drug or multiple drugs from a multi-layered matrix at rates requisiteto achieve a therapeutic effect over a specified period of time, e.g.,fast and sustained, while maintaining drug concentrations below levelsknown to cause toxic symptoms. The release of drug is controlled bycomposition, size, and size distribution and internal microstructure ofthe encapsulates.

The injectable encapsulates are micro- or nano-sized encapsulates thatare (a) injectable through a 27 G-31 G needle, (b) remain dispersed intissue or tissue fluids such as the vitreous, i.e., minimal clumping,and (c) display a sustained and predictable drug release.

The internal microstructure of the encapsulates is designed to be solidwith the release rate controlled by a combination of diffusion anddegradation. The surface of the encapsulates has been designed to besmooth, with a surface coating that supports good flow characteristics.

The internal microstructure of the encapsulates can consist ofconcentric rings (cross-sections shown in FIGS. 5A and 5B), with eachring consisting of a polymer composition that is engineered to release adrug at a specific rate. The internal microstructure of the deliverysystem can be bi-axial, with two concentric rings characterizing eachaxis (See cross-sectional view, FIG. 5A), creating a core matrix and acorona matrix, each containing a drug. Alternatively, the matrix can bemonolithic, with a single homogeneous composition with incorporateddrug. Each concentric ring can be formed of a different matrix. Themicrostructure can also be multi-axial, with three or more concentricrings each containing different drugs and/or matrix components. See across-section schematic in FIG. 5B. The internal microstructure of theencapsulates can be co-axial with multiple axes within a larger axis(FIG. 5C). The shape of the encapsulates can be cylindrical, disc-like,spherical, square, and rectangular, depending upon the process utilizedto fabricate the encapsulates. The internal cross-sectionalmicrostructure of the encapsulates is multi-layered, with thearchitecture and thickness of each layer specific and defined. Thecomposition of each layer is varied by varying the composition ofpolymer blends used to fabricate each layer. The composition of thepolymer blend in each layer can be varied to modulate the release ofdrug.

The microstructure of the encapsulates can consist of localized regionsof one polymer composition (discontinuous phase) contained in anotherpolymer composition that comprise the continuous phase of the matrix(see FIG. 5C).

In one embodiment, the first layer consists of a first drug incorporatedin a polymeric matrix, the composition of which is engineered to releasethe first drug at a certain rate (rate 1). The second layer consists ofa second drug incorporated in a polymer matrix, the composition of whichis engineered to release the second drug at another rate (rate 2). Inone example, the matrix in layer 1 containing the first drug can releasethe drug within hours, weeks, or months, while the matrix in layer 2containing the second drug can also release the drug within hours,weeks, or months.

The drug may be the same in each matrix. Alternatively, the drug may bedifferent for each matrix.

The size of the encapsulates can be less than 100 nm, between 10-100 nm,101-200 nm, 201-400 nm, 401-600 nm, 601-800 nm, 801-1000 nm, 1 micron-10microns, 10-20 microns, 20-30 microns, 30-40 microns, 40-50 microns,50-60 microns, 60-70 microns, 70-80 microns, 80-100 microns, 100-150microns, 150-300 microns, 300 microns-1000 microns. If rod-like, in oneembodiment, the aspect ratio of the encapsulates can be 1:1, 1:2, 1:3,1:4, 1:5, 1:6, 1:7, 1:8, 1:9 and 1:10. The shape of the encapsulates maybe rod-shaped, wafer-like, discoid, cuboid, cylindrical and rectangular.

The matrices forming the encapsulates can be biodegradable, with therate of biodegradation modulated by combining various biodegradablepolymers. The biodegradable polymers can be, but are not limited to,polydioxanone, PLG, PCL, poly(caprolactone-co-glycolide),poly(esteramide), poly(trimethylene carbonate), poly(ethyleneoxide-co-lactide), polyethylene glycol and combinations thereof. Inanother embodiment, the matrices may be blended with polymers andexcipients that lend biocompatibility such as PVA, hyaluronic acids ofdifferent molecular weights, chitosans of various molecular weights,PEG-cholesterols, albumins, lecithins, phosphatidyl choline,phosphatidic acid, lauric acid, stearic acid, myristic acid, sorbitans,PEG-castor oils, capric acid, vitamin E-PEGs, PEG-fatty acids andcombinations of these ingredients.

To lessen or prevent aggregation in-vivo, the surface characteristics ofthe encapsulates can be optimized to be non-adherent to each other andto the tissue space.

One way to enhance dispersion into the tissues is to optimize thesurface of the encapsulates with coatings that provide “slippage” intothe crevices of the tissues. To that end, coatings that are PEG-based,or polysiloxane-based, among others, can be used. Molecules such assilicones, lecithins, phosphatidyl cholines, albumins, and collagen canalso be used for this purpose. The dispersion of the encapsulates in theinjectable formulation will result in efficient dispersion of the drugwithin the tissue.

The encapsulates can be prepared by melt extrusion or melt spinningtechniques through mono-axial, di-axial, or tri-axial tube needles,following by cutting to a precise size.

In another embodiment, the drug molecules being released are identical,with each matrix layer releasing the drug at a different rate, toachieve for example, a burst initial release of drug from one layer,followed by a slower sustained release of drug from another layer.

Other methods of fabricating the encapsulates are 3D printing,electro-spinning through co-axial needles followed by cutting thefilaments to size, and formation of core-shell microspheres bywater-oil-water, oil-water, or oil/oil techniques.

Drugs can be encapsulated in biodegradable micro spheres by dissolutionof the drug and the polymer in an organic solvent, then generatinguniform “droplets” by ultrasonic spraying into a solvent system thatprecipitates the polymer-encapsulated drug into spheres. The size can becontrolled by controlling the size of the droplets. The precipitatingbath may contain a silicone polymer, or an ingredient that incorporatesa slippage inducing excipient onto the surface of the microspheres. Theprecipitating bath may contain a water-soluble polyurethane withemulsifying properties.

In another example of efficient and beneficial dispersion, thedrug-containing encapsulates are injected into the sub-choroidal spaceof the eye. The encapsulates are designed to disperse and spread in thisspace surrounding the retina. Drug from the matrices in the encapsulatescan be released into the retina in a uniform flux. In another examplewhere continued dispersion is beneficial, the encapsulate can bemanufactured to remain discreet and punctate, releasing a predictedamount of drug per unit time.

The encapsulates in the injectable formulation can be surface-coatedwith excipients that are known dispersants of particles to minimizeclumping after administration. These excipients include, but not arelimited to, PEG40-stearate, PEG-lecithin, polymers of the structurePEO-PPO-PEO, glycocholic acid, and cholic acid. The coating on theencapsulates may be positively charged, negatively charged, or neutral.

In another example, the encapsulates can be surface-coated withsilicones by ultrasonic spraying. In another method to prepare“non-stick” injectable encapsulates, surface coating may be added by awashing step that contains injectable silicone and ethanol, enablingdeposition of a very fine layer of silicone. Only injectable siliconesare utilized for this purpose. Microspheres that have been coated withsilicones will “roll” when injected and will immediately disperse.

In another example, the encapsulates can be spray-coated with silica,titanium dioxide, albumin, or polyvinyl alcohol.

In one example, the encapsulates are dispersed in a biocompatible gelsuch as hyaluronic acid, albumin, collagen, or combinations thereof. Inanother example, the encapsulates are dispersed in a synthetic simulatedfluid.

In another example, the encapsulates are dispersed in a biologicalfluid, such as serum plasma extracted from blood stock, a simulatedocular fluid, or amino acids and poly-amino acids found in biologicalsystems.

The injectable sustained-release formulation can be deliveredintravenously, either targeted or non-targeted. In this regard, theencapsulates in the formulation can be surface coated with a targetingantibody.

In another embodiment, the surface characteristics of the encapsulatescan be modified to encourage phagocytosis, or to elicit an appropriateimmune reaction. For example, the injectable sustained-releaseformulation can be a vaccine, either therapeutic or prophylactic. Inthat case, the encapsulates in the formulation will be targeted toantigen presenting cells to elicit the desired immune response to theantigen in question. To achieve this goal, the encapsulates can besurface-modified to have molecules that elicit phagocytic uptake bymonocytes and macrophages. For example, molecules that have adjuvantactivity can be used. Beta 1→4/1→6 glucan, zymosan, aluminum hydroxide,and other adjuvants known to those skilled in the art, may be utilized.For treating age-related macular degeneration (ARMD), the surface of theencapsulates in the formulation contain beta glucan, not just on thesurface, but also in the interior of the encapsulates as an active, oras co-active with another drug. In another example, β-amyloid can bindbeta glucan, thus acting as a homing signal for the encapsulates to bindto β-amyloid. In another embodiment, the molecules being released fromeach distinct matrix may be a combination of a therapeutic and anadjuvant.

In another embodiment, the surface characteristics of the encapsulatescan be positively charged to adhere easily to the tissue surface, or toenhance permeation into cells. The surface of the encapsulates can beoptimized to interact with the proteins in the tissue space.

The encapsulates are coated with polymers known to those skilled in theart to be compatible with and non-toxic to cells. In this connection,the encapsulates can be coated with polymers such as albumin, lecithin,phosphatidylcholine, PEG-distearoyl phosphatidyl choline(PEG2K/5K-DSPE), PEG-cholesterol, PEG, PEG-fatty acid (PEG-stearate,PEG-laureate, etc.) to prevent macro-encapsulation of the encapsulatesas they release drug over a sustained period of time.

The drug contained within the matrices of the encapsulates may behydrophilic, or hydrophobic. The drug can be a small molecule, aprotein, a peptide, a peptide nucleic acid (PNA), oligonucleotide (ODN),DNA, an aptamer, or RNA. In one embodiment, the matrices can containmultiple small molecules, each with a distinct therapeutic intent.

In one embodiment, the injectable sustained-release formulation isinjected into the conjunctival cul-de-sac of each eye to treat an ocularcondition. The encapsulates in the injectable sustained-releaseformulation release at least 10 ng per day of a bioactive agent for aperiod greater than 2 weeks. In another example, the encapsulatesrelease an effective amount of the one or more active agents for aperiod greater than 14 days in vivo, preferably greater than 60 days invivo, more preferably up to 72 days in vivo, more preferably greaterthan 90 days in vivo, even more preferably over 100 days in vivo, andmost preferably greater than 120 days in vivo.

In one embodiment, the encapsulates will be injected into ocular tissueto treat glaucoma. In one embodiment the drug is latanoprost,bimatoprost, travoprost, or their salts, esters, and prodrugs.

In another embodiment, the molecules being released from each distinctmatrix may be a combination of a therapeutic and a p-glycoprotein (PGP)inhibitor.

In another embodiment, the molecules being released are a small moleculeand a biologic, e.g., an anti-VEGF molecule to treat ARMD) and a steroidto treat inflammation. In an exemplary embodiment, the steroid istriamcinolone acetonide and the anti-VEGF molecule is avastin. Inanother example, the steroid is fluocinolone and the anti-VEGF moleculeis PEGaptanib. In a further example, the anti-VEGF molecule isranibizumab, bevacizumab, or aflibercept.

In another embodiment, the molecules being released from the matricesare an antimicrobial and a steroid. In another example, the anti-cancermolecule is an EGFR inhibitor. In one such example, the EGFR inhibitoris Ertolinib. In an example, the steroid is triamcinolone acetonide andthe antimicrobial is tobramycin. Other antimicrobials that can be usedare cortisporin, erythromycin, cyclosporin, and others in this classknown to those skilled in the art.

Examples of corticosteroids and NSAIDs that can be incorporated into oneof the matrices include, but are not limited to, dexamethasone,dexamethasone sodium phosphate, fluticasone propionate, fluticasonefuroate, and difluprednate. In one example, one of the drugs is anantihistamine. In another example, one of the drugs is an anti-allergymedication.

In one embodiment, the drug-encapsulates are delivered as an intranasalwash, or an intranasal spray. In one example, the drug-encapsulatesdeliver an anti-allergy medication and a decongestant to the nasalpassage. In another example, the intranasally-delivered matrixco-delivers an anti-allergy drug and an anti-inflammatory drug. Inanother example, the drug-encapsulates are administered to the lung as aspray-dried powder formulated with excipients made suitable forpulmonary administration. In another example, the drug-encapsulates arenebulized for pulmonary administration.

In another embodiment, one of the encapsulate layers contains atargeting moiety such as an antibody or a molecule targeting theencapsulates to a specific receptor. In this case, a second layer wouldcontain a therapeutic to treat the disease.

In another embodiment, one of the layers may contain a biocompatiblebioadhesive that can hold the delivery system to the tissue, while thelayer contains a therapeutic, either a small molecule or a biologic. Inan example, the bioadhesive molecule is polyacrylic acid and thetherapeutic is a steroid.

In another embodiment, one of the layers may contain a cell-permeatingcomponent, while the other layer contained the therapeutic. In anexample, the cell-permeating component is polysorbate 20, polysorbate60, or polysorbate 80. In another example, the cell-permeating componentis magainin, melittin, or any cell-permeating peptide known to thoseskilled in the art.

Also provided is a method for treating inflammation after cataractsurgery. The method requires injecting the sustained-release formulationhaving loteprednol-containing microencapsulates into the conjunctivalspace after cataract surgery. The micro-encapsulates will releaseloteprednol etabonate over a period of three weeks at a sustained rateof 1-5 μg/day.

One aspect to successful drug therapy is the ability to treat thepatient with multiple drugs, often with various drug release regimens.This results in the patient having to receive multiple drugs, oftenmultiple injections, or multiple pills.

Oncology treatments often involve a combined drug regimen wheremulti-drug cocktails are utilized to develop an effective therapy forthe patient. One example of a combined regimen is in the treatment ofretinoblastoma, where the drug regimen could be sustained release of twodifferent anti-cancer drugs. Another example of a combined drug regimencould be in the release of two different drugs, for the treatment ofglioblastoma. In this example, the combined drug regimen could beprecise and controlled release of a steroid and an anti-cancer drug. Inanother example, the combined drug regimen could be precise andcontrolled release of an anti-microbial and an anti-cancer drug.

In one example, the drug-containing encapsulates are small enough indimensions to be sterile-filtered. The drug-containing encapsulates canbe less than 0.22 microns in size, between 0.2-0.5 microns in size,0.5-1 microns in size, 1-2 microns in size, 2-10 microns in size, 10-20microns in size, 20-40 microns in size, 40-60 microns in size, 60-100microns in size, 100-200 microns in size, or 200-500 microns in size.

The encapsulated drug in any given matrix may be released 100% in lessthan a day, or release in a sustained manner up to 14 days, or releasein a sustained rate up to 14-30 days, or release in a sustained mannerup to 30-150 days, or release in a sustained manner up to 150-180 days,or up to one year.

The therapeutic agents utilized with the drug-containing encapsulatescan include one or more drugs set forth below, either alone or incombination. The drugs utilized may also be the equivalent of,derivatives of, or analogs of one or more of the drugs listed below. Thedrugs may include but are not limited to pharmaceutical agents includinganti-glaucoma medications, ocular agents, antimicrobial agents (e.g.,antibiotic, antiviral, antiparasitic, antifungal agents),anti-inflammatory agents (including steroids or non-steroidalanti-inflammatory), biological agents including hormones, enzymes orenzyme-related components, antibodies or antibody-related components,oligonucleotides (including DNA, RNA, short-interfering RNA, antisenseoligonucleotides, and the like), DNA/RNA vectors, viruses (either wildtype or genetically modified) or viral vectors, peptides, proteins,enzymes, extracellular matrix components, and live cells configured toproduce one or more biological components.

Another example of a combined regimen would be in the treatment ofmacular edema caused by diabetic retinopathy (DR), or ARMD, among otherposterior eye diseases. Since the macular edema is caused byinflammatory factors, it is often necessary to prescribe steroids oranti-inflammatory medications, also delivered by injections. Theinjectable sustained drug delivery system, which can release sustained,constant rates of multiple drugs simultaneously, could significantlyalter the landscape of therapies available for these ocular diseases.Similarly, front-of-the-eye diseases can be treated by a singleinjectable sustained release drug delivery formulation that couldrelease sustained, constant rates of multiple drugs.

Another example of a drug combination regimen that can be accomplishedusing the injectable sustained-release formulation described above issustained release of an antibiotic and an anti-inflammatory aftersurgery. Examples of anti-inflammatories and analgesics used aftercataract surgery are bromfenac, nevanac, durezol, fluticasonepropionate, fluticasone furoate, dexamethasone, triamcinolone acetonide,ketorolac Tromethamine, flurbiprofen, morphine, and codeine.

One embodiment of a two drug-combination regimen is sustained release ofan anti-microbial agent and an anti-inflammatory for the treatment ofdermis-related diseases. In one example, the anti-microbial is ananti-fungal molecule. One embodiment of combined drug treatment could bein the treatment of urological diseases, with a concomitantadministration of an antimicrobial and an anti-inflammatory. In anotherembodiment, the combined regimen is the administration of an imagingagent and a therapeutic.

In other embodiments, the injectable sustained-release formulation canbe used for treating dermal disorders, CNS disorders, GI disorders,Alzheimer's disease or other disease of the brain, cardiovasculardiseases, rectal diseases, and vaginal diseases.

In another embodiment, the injectable sustained-release formulation canbe used for diagnostics. In another embodiment, the injectablesustained-release formulation can be used to deliver cosmetics orsubstances to improve appearance of the skin. In another example, theinjectable sustained-release formulation can be utilized to deliver atherapeutic and a cosmetic.

The injectable sustained-release formulation can be incorporated intowound dressings.

Without further elaboration, it is believed that one skilled in the artcan, based on the description above, utilize the present invention toits fullest extent. The specific examples below are to be construed asmerely illustrative, and not limitative of the remainder of thedisclosure in any way whatsoever.

EXAMPLES Example 1 Fabrication and Characterization of Nanomesh WaferContaining Travoprost Fabrication

In this example, drug-loaded nanomesh wafers were prepared byelectrospinning. This process makes use of electrostatic and mechanicalforce to spin fibers from the tip of a fine spinneret (See FIG. 1B). Thespinneret is maintained at positive or negative charge by a DC powersupply. When the electrostatic repelling force overcomes the surfacetension force of the polymer solution, the liquid spills out of thespinneret and forms an extremely fine continuous filament. The dry meshthus produced is porous and flexible, allowing it to be cut to a desiredsize. Raw materials were travoprost (Cayman Chemicals), PLGA RG503H(Evonik), PEG40-Stearate (Sigma-Aldrich), PEG3.35K (Carbowax), F127(Spectrum), and PVP (Plastone, ISP).

Factors that control mesh properties are process conditions, molecularweight, conductivity of the solution, pH of the solution, distance fromthe tip to the collector and viscosity of the solution. Percent swellingof the mesh is controlled by the composition of the mesh; a mesh withhigh water-soluble content had higher hydration. For the purpose of anocular insert, rapid hydration of the mesh causes formation of atissue-compatible matrix.

TABLE 1 Solutions to prepare Nanomesh Wafer with Travoprost Compositionof Solution in the Syringe Prior to Electrospinning % (w/w) in solutionPEG40- Ethyl Lot No. Travoprost PEG3.33K F127 Stearate RG503H acetateEthanol DMSO ML-ES- 3.00 0 0 3.15 26.87 61.77 7.27 / 06-5 ML-ES- 3.04 00 6.95 27.13 61.03 3.82 / 06-7 ML-ES- 3.04 0 3.13 0 27.05 61.65 0.07 /06-8 ML-ES- 2.96 0 6.95 0 27.38 60.97 0.04 / 06-11 ML-ES- 2.99 3.16 0 026.93 61.47 0.07 / 06-12 ML-ES- 3.02 3.04 0 0 27.16 61.30 27.43 0.0506-16 ML-ES- 2.97 0 0.75 0.75 27.17 61.78 8.67 / 06-21 ML-ES- 2.93 01.50 0.77 27.6 62.10 7.14 / 06-31

TABLE 2 Theoretical Composition of Ingredients in Nanomesh WaferComposition of Each Ingredient % (w/w) in Nanomesh PEG40- Lot No. VisualTravoprost PEG3.33K F127 PVP Stearate RG503H ML-ES-06-5 Flexible 3.00 00 0 10.17 86.78 uniform ML-ES-06-7 Flexible 3.04 0 0 0 19.78 77.19uniform ML-ES-06-8 Flexible 3.04 0 10.06 0 0 86.90 uniform ML-ES-06-11Flexible 2.96 0 19.64 0 0 77.40 uniform ML-ES-06-12 Flexible 2.99 10.200 0 0 86.81 uniform ML-ES-06-16 Flexible 3.02 0 0 9.76 0 87.21 uniformML-ES-06-21 Flexible 2.97 0 2.54 2.54 91.95 uniform ML-ES-06-31 Flexible2.93 0 4.91 2.49 89.69 uniform

TABLE 3 Nanofiber Electrospinning Conditions Distance from Flow RateVoltage Needle Tip to Collector Lot No. (mL/hour) (kV) (gauge) (inches)Cycle ML-ES-06-5 0.8 20 22 3.25 15 ML-ES-06-7 0.8 20 22 3.25 15ML-ES-06-8 1.5 22 22 3.25 15 ML-ES-06-11 1.5 22 22 3.25 15 ML-ES-06-121.5 22 22 3.25 15 ML-ES-06-16 2 16 22 3.25 15 ML-ES-06-21 2 16 22 3.2515 ML-ES-06-31 2 16 22 3.25 15

The estimated travoprost content is 0.1575 mg for a prototype that is 10mm×1.5 mm×0.22 mm (length×width×thickness). In a 30 day release profile,this would provide approximately 5.25 μg/day released on the ocularsurface for absorption. It is estimated that 1.5 μg /day is needed foreffective glaucoma therapy.

The thickness of the nanomesh was measured by a micrometer screw gauge(n=3). The results are shown in Table 4 below.

TABLE 4 Thickness of Nanomesh Wafer Prototypes sample n = 1^(a) n =2^(a) n = 3^(a) AVERAGE^(a) STDEV RSD ML-06-5 0.07 0.07 0.07 0.07 0.0000.00% ML-06-7 0.06 0.06 0.05 0.06 0.006 10.19% ML-06-8 0.09 0.08 0.080.08 0.006 6.93% ML-06-11 0.08 0.09 0.09 0.09 0.006 6.66% ML-06-12 0.060.06 0.06 0.06 0.000 0.00% ML-06-16 0.08 0.09 0.08 0.08 0.006 6.93%ML-06-21 0.10 0.10 0.11 0.10 0.006 5.59% ML-06-31 0.08 0.08 0.08 0.080.000 0.00% ML-06-74 0.16 0.15 0.14 0.15 0.010 6.67% ML-06-77 0.13 0.150.16 0.15 0.015 10.41% ML-06-81 0.20 0.22 0.23 0.22 0.015 7.05% ML-06-840.17 0.16 0.17 0.17 0.006 3.46% ML-06-88 0.31 0.30 0.28 0.30 0.015 5.15%ML-07-07 0.07 0.07 0.09 0.08 0.012 15.06% ML-07-08 0.48 0.44 0.45 0.460.021 4.56% ^(a)values are thickness in mm

Encapsulation

To determine the percent drug encapsulation, travoprost encapsulated innanomesh was dissolved first in acetonitrile. The polymer isprecipitated in an aqueous phase and the supernatant analyzed by HPLC.Encapsulation is calculated by the following formula:

${{Travoprost}\mspace{14mu} {encapsulation}\mspace{14mu} \left( {{mg}\text{/}g} \right)} = \frac{\begin{matrix}{{Travoprost}\left( \frac{{mg}\mspace{14mu} {Travoprost}}{g\mspace{14mu} {extraction}\mspace{14mu} {solution}} \right) \times} \\{{Total}\mspace{14mu} {mass}\mspace{14mu} {of}\mspace{14mu} {extraction}\mspace{14mu} {solution}\mspace{14mu} (g)}\end{matrix}}{{Mass}\mspace{14mu} {of}\mspace{14mu} {nanomesh}\mspace{14mu} (g)}$

The amount of travoprost in samples was determined by HPLC. For thisanalysis, a stock solution was prepared gravimetrically by weighing out9.5 mg of travoprost and dissolving it in 0.9416 g methanol in a 1.5 mLcentrifuge tube. This yielded a 9.9884 mg/g travoprost stock solution.Standards were prepared with concentrations between 0.007 and 142 μg/g,series diluted from the original 9.9884 mg/g travoprost stock solution.Standards prepared had a range of 0.00692 and 14.79 μg/mL. Analysis wasconducted using a gradient program and Zorbax RP C-18 4.6×150 mm column,with a flow rate of 1 mL/min, 37° C., 220 nm, 20 minutes, 40 μL.Travoprost has a retention time of 19 minutes.

As shown below in TABLE 5 below, the percent encapsulation of theprototypes varied between 79-85%.

TABLE 5 Travoprost Encapsulation in Nanomesh Encapsulation Lot# (mgtravoprost/g mesh) % Encapsulation ML-ES-06-5 25.07 82.20 ML-ES-06-725.84 85.28 ML-ES-06-8 24.14 79.41 ML-ES-06-11 25.43 85.62 ML-ES-06-1227.00 90.30 ML-ES-06-16 24.96 82.65 ML-ES-06-21 26.16 88.08 ML-ES-06-3125.73 87.82

Hydration

The rate of water absorption by nanomesh wafers was measured as afunction of time. The hydration was performed using dry wafers incubatedin buffer at 37° C. The results, shown in Table 6 below, indicated thatthe percent hydration was high when the hydrophilic component of thewafer was high. For wafers that had high hydrophobic content (e.g.,ML-ES-06-7), hydration was relatively lower. In-vivo studies can be usedto demonstrate if fast hydration kinetics results in delamination of thewafer from the ocular tissue.

TABLE 6 Hydration Kinetics of Nanowafer Prototypes Final Composition inDried Appearance Nanomesh after Batch# Wafer T = 10 m T = 20 m T = 30 mT = 40 m hydration ML-ES-06-5 10.17% 149.32 146.58 154.79 154.79 Intact,PEG40- flexible Stearate/3% TP/ ML-ES-06-7 19.78% PEG 44.90 75.51 32.6551.02 Intact, Stearate/ flexible ML-ES-06-8 10% Pluronic 147.06 155.88151.96 148.04 Intact, F127 flexible ML-ES-06-11 20% Pluronic 56.38 57.4559.57 56.38 Intact, F127 flexible ML-ES-06-12 10% 76.62 90.91 94.1690.91 Intact, PEG3.35k flexible ML-ES-06-16 10% PVP 43.71 55.09 53.8955.09 Intact, flexible ML-ES-06-21 2.5% PEG-S 192.23 195.15 200 185.44Intact, & 2.5% F127 flexible ML-ES-06-31 2.5% PEG-S 251.16 258.14 265.12267.44 Intact, & 5% F127 flexible

Scanning Electron Microscopy

Scanning electron micrographs (SEMs) of prototypes showed a finelydivided mesh nanostructure, with an open-celled structure withindividual fibers between 200 nm and 5 microns in diameter. See FIG. 1C.The open cell structure allows free flow of fluids through the nanomeshwafer, a critical feature for a biocompatible insert.

In-Vitro Release

In-vitro release experiments with nanomesh wafers were conducted with100 mg of wafer placed in Float-y-lyzer and incubated in buffersolutions at pH 7.4 and 37° C. The buffer contained 1% hydroxypropylβ-cyclodextrin (HPCD) in phosphate buffered saline (PBS). As shown inFIGS. 2A to 2D, in-vitro release of travoprost could be modulated bychanges in the nanomesh composition.

Biodegradation and Potential for Local Irritation:

The potential risk for irritation in an ocular product is always aconcern. To address this, an in-vitro study was conducted to ascertainthe surface pH of the drug delivery system as it biodegraded andreleased drug into the buffer medium. A sensitive pH micro-probe wasutilized to measure the surface pH of the system, on a nanomesh waferprototype (ML-ES-06-31). The surface pH of the drug delivery systemnever fell dramatically; the pH fluctuated in the range of 6.9 to 7.2for the duration of the study. See FIG. 3B. It is anticipated that thefluid turnover in an in-vivo scenario will wash out the low molar levelsof lactic acid and/or glycolic acid released from the nanomesh wafer asit biodegrades.

Photo-Oxidation Stress:

Nanomesh wafers (ML-ES-06-31) were tested for photo-oxidativedegradation by high intensity UV light (254 nm, for 24 hours). The datademonstrated that >98% of the encapsulated travoprost was intact,indicating protection of the drug from UV light exposure during use. Incontrast, 50% of the travoprost in buffer alone was degraded under theseconditions.

Corneal Permeability Study:

Franz-cell corneal permeability studies were performed onTravoprost-containing nanomesh wafers (ML-ES-06-31). Fresh bovine calfcorneas were loaded on the Franz diffusion cells. Nanomesh samples werepunch-cut to have diameters of 5.28 mm and placed on the corneas. Thesamples were wet with 20 μL of buffer. The receptor chambers was filledwith fresh 1% HPCD buffer. Time-points were once hourly for 8 hours andonce after 18 hours. Samples were analyzed using a reverse-phase HPLCmethod. The corneas were retrieved from the chambers and extracted fordrug content. FIG. 3A demonstrates that the encapsulated travoprostsuccessfully diffuses through the bovine cornea to be converted intotravoprost acid, the active form of the drug.

Example 2 Biocompatibility Screening of Prototypes

In-vitro eye irritation testing of three nanomesh wafer prototypes weretested for eye irritation using three-dimensional corneal tissueconstructs purchased from Mattek Corporation, MA. Three nanomesh waferprototypes were contact-exposed to the corneal tissue constructs using apublished protocol. See Kandarova et al., Toxicology Letters 211,Supplement, 17 Jun. 2012, pages S111-S112, the content of which isincorporated herein in its entirety.

More than 60% cell viability is classified as “NI” (non-irritating). Itwas observed that the maximum thickness of a wafer should be no morethan 0.5 mm to be non-irritating.

Example 3 Ocular Irritation in Rabbit Eyes

In vivo studies with the nanomesh wafers are conducted in normotensiveNew England White rabbits at Toxikon Corp, Bedford, Mass. Sterile meshesare inserted (blank nanomesh in one eye, travoprost-nanomesh in theopposite eye, n=6 rabbits) into the conjunctival cul-de-sac of each eyeof the rabbit. Each eye is examined according to the McDonald-ShattuckClassification Grading Ocular Lesions prior to, and at specifictime-points after placement of a travoprost-containing nanomesh wafer inone eye and a blank nanomesh wafer in the opposite eye. The followingparameters are evaluated: Slit-lamp exam to include signs of ocularsurface irritation (conjunctival hyperemia, chemosis, discharge, cornealopacity and fluorescein staining), inflammation (anterior chamber cellsand flare, iritis), pupil diameter (calipers), and IOP (TonoVet reboundtonometer). Tear samples are collected using Schirmer strips forbioanalysis of travoprost and travoprost acid. On day 1, evaluations areconducted at baseline, 0.25, 0.5, 1, 2, 4, and 8 hours after nanomeshplacement, followed by twice daily evaluations on days 2 and 3, thenweekly for a total of 4 weeks. If at any point, severe irritation orinflammation is observed, e.g., persistent redness, discharge, chemosis,corneal staining, or cells and flare Grade 2 or higher, the nanomesh isremoved and the animal will be allowed to recover. Minimal or noirritation is observed during the study duration for all nanomeshgroups.

Example 4 Correlation of Biocompatibility with Modulus

Nanomesh prototypes are optimized to match the hydrated flexural modulusof the ocular conjunctiva. The optimal moduli range for a nanomesh waferis ideally <25 MPa to be biocompatible.

Example 5 Correlation of Oxygen Permeability with Biocompatibility

Oxygen permeability correlates with irritation in ocular tissues. Theoptimal oxygen permeability range for nanomesh wafers is in the range of20-30 Dk.

Example 6 Fabrication and Characterization of Nanomesh with LoteprednolEtabonate

TABLE 7 Solution Preparation for Loteprednol Etabonate NanomeshComposition % in mesh % in solution Lot No. API 20 RG503H Ethyl acetateEthanol ML-ES-03-48 6.53 0.74 26.56 59.56 11.19 ML-ES-03-50 10.15 0.7126.74 59.20 10.25

TABLE 8 Loteprednol Etabonate in Nanofiber Electrospinning ConditionsDistance of Flow Rate Voltage Needle Tip to Collector Lot No. (mL/hour)(kV) (gauge) (inch) Cycle ML-ES-03-48 0.8 20 22 3.25 20 ML-ES-03-50 0.820 22 3.25 15

TABLE 9 Characterization of Loteprednol Etabonate in Nanomesh % ReleaseEncapsulation Burst (40 % Thickness Flex Visual Lot No. (mg/g) (%) Days)Hydration (mm) Strength^(a) Uniformity^(b) ML-ES-03-48 61.77 0 99.0880.0 0.15 1 1 ML-ES-03-50 96.27 0 55.09 89.3 0.10 1 1 ^(a)Flex Strengthclassify as Excellent (1), Good (2), Needs Improvement (3), Crumbles(4); ^(b)Visual Uniformity classify as Excellent (1), Non-uniform inplaces (2) and Random/Non-uniform (3).

Thickness for these two nanomesh wafers were measured three times onthree random areas. The standard deviation below 0.01 revealed theuniformity of loteprednol etabonate nanomesh wafers.

The total amount of encapsulated travoprost in each nanomesh wafer wasmeasured by HPLC. The encapsulation for ML-ES-03-48 was 61.77 mg/g whichwas close to the target 6% in the mesh, and the encapsulation forML-ES-03-50 was 96.27 mg/g which was also close to the target 10% in themesh.

None of these nanomesh prototypes released drug in 1 hour. For in vitrorelease, ML-ES-03-48 released 99.08% in 40 days, which was close to adesired target of releasing 100% in 30 days, while the cumulativerelease of ML-ES-03-50 in 40 days was comparatively slow, which may haveresulted from lower PEG.S than ML-ES-03-48. The flexural strength ofthese two nanomesh wafer prototypes was excellent. They can both be bentand flexed between thumb and index finger. It was observed thatML-ES-03-48 and ML-ES-03-50 were made uniformly.

Example 7 Fabrication of Nanomesh with Surface Reactive Moieties

Nanomesh wafers can be prepared by incorporating 5% 4-armPEG3K-succinimidyl glutarate (SG) and 4-arm 5% PEG-NH₂ with 26% PLGA(RG503H), 0.7% PEG-Stearate in the electrospinning solution in the samesolvents shown in Table 7 above, with 49% ethyl acetate and 11% ethanoland the active pharmaceutical ingredient (API), in this case,loteprednol etabonate. The conditions of the electrospinning are shownin Table 8 above.

Example 8 Fabrication and Characterization of Loteprednol Etabonate inPLG Microencapsulates

Loteprednol etabonate is a “soft” steroid which is rapidly convertedinto inactive metabolites by nonspecific esterases in the ocular tissue.A micro-encapsulated loteprednol etabonate injectable sustained-releaseformulation is disclosed that can be injected in the conjunctival sacimmediately after surgery. For control of inflammation after cataractsurgery, the injectable sustained-release formulation is designed torelease a drug over a 2 to 3 week period with a single injection.

PLG was used as the biodegradable polymer microencapsulate. The roles ofmolecular weight, structure, and size of the microencapsulates on therelease profile of loteprednol etabonate were investigated, as well asinjectability as a function of size.

Preparation of Micro-Encapsulates:

PLG microencapsulates were prepared by an emulsion process to achieve anarrow size distribution, optimum size, and injectability. Loteprednoletabonate was purchased from Sigma, Inc. PLG (50:50 L:G) of differentmolecular weights were utilized to assess effect on in-vitro release. Ablend of PLG terminated with acid end groups and ester end groups wereprepared to assess the effect on in-vitro drug release. Themicroencapsulates were prepared as follows:

a. A stock solution of 8% polyvinyl alcohol (PVA) was prepared by addingsolid PVA to distilled water while stirring, and then heating to 80° C.When fully dissolved, the solution was allowed to cool back down to 25°C., and then 53 g of the solution was aliquoted for Phase IIpreparation. A 9.46% sodium chloride solution was prepared separatelyfrom the 8% PVA. The sodium chloride was poured into the PVA solutionslowly, while the PVA solution was stirring. 3.6 grams of ethyl acetatewas added to the Phase II. The Phase II was then covered andrefrigerated at 4° C. Prior to homogenization, the Phase II was pouredinto a jacketed vessel when it had reached 0° C.

b. A 50/50 v/v mixture of ethanol and ethyl acetate was prepared. Theweights were obtained and recorded. Loteprednol etabonate was dissolvedin this mixture to create a 30 mg/mL solution of loteprednol etabonate.In exemplary formulation KB-ES-02-55, the loteprednol solution alsocontained 5% w/w PE/F-127.

c. PLG was dissolved in ethyl acetate to create a 5.2% solution. 1 mL ofthe loteprednol etabonate stock solution was aliquoted into the PLGsolution while it stirred. The completed Phase I was taken up into aHamilton #1010 Gastight syringe fitted with 14 ga tubing. The Phase Iwas used immediately after preparation. It should not be left at roomtemperature, nor should it be refrigerated. The homogenization run wasstarted, and the Phase I was injected into the Phase II to generate anemulsion, i.e., Phase III. Immediately afterward, the Phase III waspoured into additional H₂O to create the final microsphere suspension.

d. After 6 minutes of homogenization, the jacketed vessel was moved to apaddle mixer and stirred for 3 h at 450 RPM. During this step, the firsthour of stirring was conducted at 0° C. Then, the temperature was raisedto 17° C. for 20 min., then 27° C. for 20 min., and then 35° C. for theremaining time. After 3 h elapsed, the suspension was cooled to 10° C.and pipetted into 50 mL centrifuge tubes. The samples were centrifuged 3times at 10000 RPM, 10° C.

e. The first centrifugation cycle results in a pellet of microspheresand a supernatant composed of the bulk of the PVA, NaCl, and remainingethyl acetate.

f. The microencapsulates were washed four times with 4° C. distilledwater and the pellets combined into one. The microencapsulates weresprayed with dimethicone in isopropanol to provide a non-aggregatingsurface.

g. The combined pellet was re-suspended and washed with 5-10 mL ofchilled distilled water, in a 100 mL beaker. The beaker was covered witha lint-free paper and then placed in a lyophilizer for drying.

Characterization of Microencapsulates: Particle Size Distribution (PSD):

Samples were suspended 20 mg/mL in a diluent, diluted with an equivalentvolume of water. 500 μL of the suspension was dispersed in a dispersalmedium (a thirty fold dilution of the diluent in distilled water).Particle size was measured on a Horiba LA-950 Laser Diffraction ParticleAnalyzer.

Imaging:

Dry encapsulates were characterized by scanning electron microscopy.

Encapsulation (mg/G):

20 mg of the microencapsulate was dissolved in 1 mL of acetonitrile, and10 mL of isopropanol added drop-wise while mixing. 1 mL of the slurrywas centrifuged (5 min.; 6000 RPM), and the supernatant was removed forHPLC analysis. HPLC analysis was performed on a RP C18 column.

Compatibility:

The compatibility of PLG and loteprednol etabonate was assessed bycomparison of their HPLC profiles.

In-Vitro Burst (%):

30 mg of the microencapsulates were reconstituted in 1 mL of PBS, pH 7.4and rotated at 37° C., in a 2 mL polypropylene centrifuge tube. At the 1hour time-point, the centrifuge tubes were spun down at 15,000 RPM. OnemL of the supernatant was removed for analysis by HPLC.

In-Vitro Release:

200-300 mg of microencapsulates were weighed into 1 mL SpectraPorcassettes (cellulose membranes, MWCO 1000 kDal). The cassettescontaining the microencapsulates were placed in 45 mL of PBS andincubated at 50° C. Time point samples were obtained after 1 hour anddaily over the course of 20 days. The samples were analyzed by HPLC.

Injectability:

Injectability of the microencapsulates suspended in the reconstitutingfluid was tested both through 23 G and 27 G needles.

The results of the analysis are presented in Table 10 below. The datademonstrated that loteprednol etabonate could be encapsulatedsuccessfully in PLG-based microencapsulates. The size distribution ofthe microencapsulates can be modulated by control of process conditions,with a range of sizes between 9.3-40.4 microns (d₅₀). An acceleratedin-vitro release test was developed to enable fast screening ofprototypes to assess difference in in-vitro release of drug produced asa function of size, polymer structure and molecular weight. Through thistest, it was ascertained that

PLG of higher molecular weight and larger size (KB-05-01) released drugvery slowly, as opposed to a blend prototype of ester end and acid endPLG (50:50 L:G) (KB-05-34). Surprisingly, the release rate of drug fromester end group PLG microencapsulates (KB-05-25B) was greater that thatrate from acid end group PLG microencapsulates (KB-05-28) at the same MW(0.21 dl/g).

All batches were injectable through 27 G needles for the entire sizerange of the prototypes, which renders it feasible for injection inocular tissue. PLG polymers and loteprednol etabonate were deemedcompatible. All PLG microencapsulates were designed to have a solidmicrostructure.

TABLE 10 Characterization of Loteprednol Etabonate- ContainingMicroencapsulates Intrinsic PSD Lo# Polymer Name Viscosity Encap.(d₅₀/d₉₀) KB-05-01 Purasorb 5004A; 0.39 dl/g 187.9 mg/g  40.4/67  50/50L:G KB-05-25A Purasorb 5002;  0.2 dl/g 19.8 mg/g  15/41.9 50/50 L:GKB-05-25B Purasorb 5002;  0.2 dl/g 29.4 mg/g 16.7/37.2 50/50 L:GKB-05-28 Purasorb 5002A; 0.21 dl/g 47.5 mg/g 11.6/24.3 50/50 L:GKB-05-34 Mix: A 50/50 0.21 dl/g 14.9 mg/g 9.3/21  combination ofPurasorb 5002 and 5002A, both 50/50 L:G

Other Embodiments

All of the features disclosed in this specification may be combined inany combination. Each feature disclosed in this specification may bereplaced by an alternative feature serving the same, equivalent, orsimilar purpose. Thus, unless expressly stated otherwise, each featuredisclosed is only an example of a generic series of equivalent orsimilar features.

From the above description, a person skilled in the art can easilyascertain the essential characteristics of the present invention, andwithout departing from the spirit and scope thereof, can make variouschanges and modifications of the present invention to adapt it tovarious usages and conditions. Thus, other embodiments are also withinthe claims.

What is claimed is:
 1. A nanostructured biocompatible wafer for drugdelivery to a tissue, the wafer comprising a tissue-reactivemucoadhesive polymer and a mesh formed of a plurality of polymer fibers,wherein the tissue-reactive mucoadhesive polymer is coated on the waferor intercalated with the fibers, the wafer has a hydrated flexuralmodulus less than 25 MPa, the mesh has a pore size of 50 nm to 1000 nm,and the polymer fibers have a diameter of 100 nm to 1500 nm.
 2. Thenanostructured biocompatible wafer of claim 1, wherein the polymerfibers are formed of the polymers selected from the group consisting ofpolylactide-co-glycolide, polylactic acid, polycaprolactone,poly(trimethylene carbonate), poly(amino acids), hyaluronic acid,polyethylene glycol (PEG), polyethylene oxide-polypropyleneoxide-polyethylene oxide tri-block copolymer, PEG-stearate,PEG-distearoyl-sn-glycero-3-phosphoethanolamine, lecithin, xanthan,polyvinylalcohol, polyvinylpyrrolidone, albumin, collagen, polysiloxane,polymethylmethacrylate, and a is combination thereof.
 3. Thenanostructured biocompatible wafer of claim 1, wherein thetissue-reactive mucoadhesive polymer is selected from the groupconsisting of xanthan gum, guar gum, chitosan, hyaluronic acid,alginate, xyloglucans, polycarbophil, polyacrylic acid, tamarind seedpolysaccharide, PEG-succinimidyl glutarate, PEG-amine, polylysine, and acombination thereof.
 4. The nanostructured biocompatible wafer of claim1, wherein the polymer fibers are monolithic fibers and thetissue-reactive mucoadhesive polymer is intercalated with the polymerfibers.
 5. The nanostructured biocompatible wafer of claim 4, furthercomprising a wound healing component selected from 1→3 beta glucan, 1→6beta glucan, tamarind seed polysaccharide, albumin, lecithin, collagen,and hyaluronic acid.
 6. The nanostructured biocompatible wafer of claim4, further comprising succinimidyl, thiol, or amine moieties for bindingto the tissue via ionic binding or light complexation to proteins on asurface of the tissue.
 7. The nanostructured biocompatible wafer ofclaim 1, wherein the mesh is formed of a plurality of co-axial fiberseach having a core containing the plurality of polymer fibers and anouter layer containing the tissue-reactive mucoadhesive polymer.
 8. Thenanostructured biocompatible wafer of claim 7, further comprising awound healing component selected from 1→3 beta glucan, 1→6 beta glucan,tamarind seed polysaccharide, albumin, lecithin, collagen, andhyaluronic acid.
 9. The nanostructured biocompatible wafer of claim 7,further comprising succinimidyl, thiol, or amine moieties for binding tothe tissue via ionic binding or light complexation to proteins on asurface of the tissue.
 10. The nanostructured biocompatible wafer ofclaim 1, wherein the wafer has an oxygen permeability of 15 Dk to 30 Dk.11. The nanostructured biocompatible wafer of claim 1, wherein the waferhas a thickness of 0.05 mm to 0.5 mm.
 12. The nanostructuredbiocompatible wafer of claim 1, further comprising a first drugcontained within the polymer fibers.
 13. The nanostructuredbiocompatible wafer of claim 12, wherein the first drug is a smallmolecule, a protein, a peptide, or a nucleic acid.
 14. Thenanostructured biocompatible wafer of claim 1, further comprising afirst drug contained in microparticles deposited on the polymer fibers.15. The nanostructured biocompatible wafer of claim 12, wherein thefirst drug is an anti-glaucoma agent, an anti-viral agent, ananti-inflammatory steroid, a non-steroidal anti-inflammatory, ananti-fungal agent, an anti-bacterial agent, an anti-allergy agent, anagent to treat dry eye, a wound healing agent, an agent to heal ocularinjury, an analgesic, an anesthetic or an agent to treat rosacea. 16.The nanostructured biocompatible wafer of claim 12, further comprising asecond drug different from the first drug, wherein the polymer fibersare co-axial fibers having an inner layer formed of a first polymer andan outer layer formed of a second polymer, the first drug beingcontained within the inner layer and the second drug being containedwithin the outer layer.
 17. The nanostructured biocompatible wafer ofclaim 16, wherein the first polymer is different from the secondpolymer.
 18. The nanostructured biocompatible wafer of claim 16, whereinthe inner layer and the outer layer are formulated to release the firstdrug and the second drug at different rates.
 19. A method for treatingan ocular disease, the method comprising identifying a subject in needof treatment, obtaining the nanostructured biocompatible wafer of claim15, placing the nanostructured biocompatible wafer onto a conjunctiva ofthe subject, and maintaining the nanostructured biocompatible wafer onthe conjunctiva for 1-180 days.
 20. A method for treating an ocularsurface disorder, the method comprising identifying a subject in need oftreatment, obtaining the nanostructured biocompatible wafer of claim 15,and placing the nanostructured biocompatible wafer onto a conjunctiva ofthe subject.
 21. The method of claim 20, wherein the ocular surfacedisorder is dry eye, rosacea, allergic conjunctivitis, glaucoma,keratitis, blepharitis, corneal tear/injury, or inflammation.
 22. Amethod for treating an ocular surface infection, the method comprisingidentifying a subject in need of treatment, obtaining the nanostructuredbiocompatible wafer of claim 15, placing the nanostructuredbiocompatible wafer into a conjunctival cul-de-sac of the subject, andmaintaining the nano structured biocompatible wafer on the conjunctivafor a period of 2 weeks to 2 months.
 23. An injectable sustained-releaseformulation for treating an ocular disorder, the formulation comprisinga drug contained within a plurality of microparticles each formed of abiodegradable polymer, and a tissue-reactive compound coated on themicroparticles, the microparticles having a size of 1 μm to 40 μm,wherein the microparticles contain 20% to 30% by weight of thebiodegradable polymer and 5% to 20% by weight of the tissue-reactivecompound.